AMC Eagle Den Forum

The Mighty 258 => The Engine => Topic started by: bonedaddy on April 12, 2012, 10:53:58 PM

Title: First swap!!
Post by: bonedaddy on April 12, 2012, 10:53:58 PM
Ok, I got back in the Eagle game....this one went 50 miles before the motor blew (that's the furthest I've made it in 3 eagles). So, I got a shot at a 76 258 long block from a jeep, and I wanna put it in my 83 SX4 4speed. Is this a direct swap? What can I expect? I've done a lot, but never this.
Title: Re: First swap!!
Post by: vangremlin on April 12, 2012, 11:14:59 PM
I believe you need a 258 from a 1980 or later so it has the necessary mounting bosses for the front end.
Title: Re: First swap!!
Post by: standup650 on April 13, 2012, 06:35:43 AM
and isn't the crank end different length? I might be wrong.
Title: Re: First swap!!
Post by: doc65 on April 13, 2012, 08:15:32 AM
Standup, there are basically 3 cranks a long snout 12 counterweight(the 76 will have that), a long snout 4 cwt, all the Eagles should have that, and a short snout 4 cwt that the later Wranglers etc had.  If building a stroker the short snout is usually slightly preferred(though the early 12 cwt is reputedly slightly stronger and and with 20lb more weight should be slightly smoother running ), but any will work with a 10 mm spacer that can be made by cutting a chunk off an old harmonic balancer.  The mounting bosses would be the only possible stopper, I just don't know the answer to that as I'm always dealing with later blocks(4.0's)
Title: Re: First swap!!
Post by: standup650 on April 13, 2012, 03:32:32 PM
Thanks for clearing that up for me. can i pm you about some 4.0 questions later?
Title: Re: First swap!!
Post by: mudkicker715 on April 13, 2012, 04:03:41 PM
Or keep it open for more advice. as more than one person knows 4.0's or strokers i'm sure.
Title: Re: First swap!!
Post by: doc65 on April 13, 2012, 06:20:10 PM
Either is fine, if it's a standard/publicly acceptable  question/comment you should probably keep it public as that way others can make input and be able to find information when searching for it.  If you have something specific to ask or comment with me about that you feel needs to move "outside" for some reason then feel free to do that as well...
Title: Re: First swap!!
Post by: hypereagle on April 13, 2012, 06:42:18 PM
Quote from: vangremlin on April 12, 2012, 11:14:59 PM
I believe you need a 258 from a 1980 or later so it has the necessary mounting bosses for the front end.
Correct. The earlier blocks won,t work. To place to bolt the diff to.
Title: Re: First swap!!
Post by: standup650 on April 13, 2012, 08:44:39 PM
Quote from: mudkicker715 on April 13, 2012, 04:03:41 PM
Or keep it open for more advice. as more than one person knows 4.0's or strokers i'm sure.
Quote from: doc65 on April 13, 2012, 06:20:10 PM
Either is fine, if it's a standard/publicly acceptable  question/comment you should probably keep it public as that way others can make input and be able to find information when searching for it.  If you have something specific to ask or comment with me about that you feel needs to move "outside" for some reason then feel free to do that as well...
Dur..... some times i for get that thats why this site is here. Thanks guys.
Title: Re: First swap!!
Post by: bonedaddy on April 15, 2012, 09:12:52 PM
Thanks guys, I really don't want to screw this up. I just wanna get it moving with limited headaches.
Next up is a 4.2 258 from an 88 wrangler. It's complete except for pulleys and brackets. What can I expect trying to get that thing in there?
Title: Re: First swap!!
Post by: carnuck on April 15, 2012, 10:23:13 PM
Change the oil pan before installing
Title: Re: First swap!!
Post by: bonedaddy on April 16, 2012, 12:19:31 AM
Everything else is a match.
Title: Re: First swap!!
Post by: bonedaddy on April 16, 2012, 12:20:22 AM
I mean, is a match???????
Title: Re: First swap!!
Post by: BenM on April 16, 2012, 01:07:50 AM
It will definitely work, and it'll have the nice aluminum valve cover. Make sure to bring your oil pump pickup and pan and the rest of the accessories over. It'll fit like a glove.
Title: Re: First swap!!
Post by: vangremlin on April 16, 2012, 12:19:08 PM
Quote from: BenM on April 16, 2012, 01:07:50 AM
It will definitely work, and it'll have the nice aluminum valve cover. Make sure to bring your oil pump pickup and pan and the rest of the accessories over. It'll fit like a glove.

Bring the whole oil pump and pickup over, I found when I did the swap the pickup didn't pair up well with the Jeep oil pump.  Plus its either to swap the whole thing instead of pulling the pickup and having to install it on a new pump.